Take a look at this great article on unit testing by my friend Andrew Stopford and Jay Flowers:
Unit Testing with NUnit, MbUnit and VSTS
With clear-cut information like this, there is no reason NOT to do unit testing.
NOTE: As of 10/1/2017, I am no longer providing training or consulting on behalf of my company. Thank you, Robert Hurlbut
MS MVP Developer Security / Visual Studio and Development TechnologiesGitHub: rhurlbut